This is not an error of duplication. The full-fledged version of this Mitzvah are many and change for those who are learning the one/three chapter a day. The Message for the day from "Bringing Heaven Down to Earth" at the end of this Mitzvah is different than that of yesterday.

Positive Mitzvah 109: Immersing in a MikvehLeviticus 15:16 "He shall bathe all his body in water"

Just as the Torah defines the different types of impurity - it also outlines the process for purification.

The Torah describes the purification process, commanding the impure person to immerse himself in a mikveh.

A mikveh is a special pool of water of a specific size.

Its water must come from a natural source, rain or a spring.

In the beginning of the universe, the entire creation emerged from water. After an impure person dips in the mikveh, he rises up as a new creation; purified and prepared to serve HaShem.

When you reach the final ascent of the climb, you cling to whatever twig or feeble root you can find to pull yourself up. And that is where we are now. Any spark of light that comes your way -- squeeze all you can from it.